Skip Nmap on empty Masscan results; handle TCP/UDP-only scans; fix ping args

[jph4cks]

Motivation

• Prevent runtime errors and invalid commands when masscan returns no results for a target.
• Ensure nmap invocation is correct for TCP-only, UDP-only, and mixed port discoveries.
• Fix incorrect subprocess argument formatting for ping to avoid unexpected behavior.

Description

• Added a guard in main() to skip nmap_scan and nmap_vuln_scan when masscan() returns an empty result for a target. (jpscan.py)
• Reworked nmap_scan() and nmap_vuln_scan() to use target_ports[ip].get('tcp', []) and get('udp', []), skip empty entries, and build protocol-specific nmap commands for TCP-only, UDP-only, and mixed cases. (jpscan.py)
• Corrected the get_mac() ping call to pass -c and 1 as separate argv entries in Popen (Popen(["ping", "-c", "1", IP])). (jpscan.py)
• Removed redundant UDP append loop and ensured command strings use the appropriate -pT:/-pU: forms when only one protocol is present. (jpscan.py)

Testing

• Ran python3 -m py_compile jpscan.py which completed successfully. (passed)
• Executed python3 jpscan.py -t 127.0.0.1 -p 1-10 -r 1000 -w 1 in the CI environment where masscan is not installed, and the script handled the no-results path and skipped nmap scans without crashing. (behavior verified)

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Codex Task